It's a non-problem under most circumstances. If you usually motor about 5 or 10 minutes each time you start the engine then you should be OK. Self-discharge during the occasional month long layup won't be that much.

I have a yamaha 20 and a small start battery that also powers a bilge pump to deal with rain, and have never had the battery run down. Have had this setup 3 years it's a 12 foot RIB.

Until pretty recently all outboards, even the big ones only trickle charged a battery, they didn't have alternators and voltage regulators.
First find out what the little Zuk has, I'd bet it simply trickle charges at a set rate regardless of battery charge like all outboards used to do, so charging up a partially depleted battery will likely never happen unless you run your dink for hours at a time.

I'd go for a small, cheapsolar panel. Even a tiny one should keep a small battery charged, and you only need and want a tiny amount of current anyway

Get a small solarcharger to keep the battery up. You can get cheap ones on ebay that overseas car companies use to keep batteries charged in cars sitting on the dock, they just plug into a a cigarette lighter. They do not put out enough to cook the bat so do not need a regulator but will keep the battery topped up.

That's also supported by my experience with our sealed lead acid tractor battery during winter months... although that's recharged by a larger alternator, and it gets a work-out if we have big snow and I have to plow for several hours on end.

One of these days, then, I'll stop in the battery store down the street and get 'er done.

The 25hp Merc on our big boat has both electric and pull start, so if the battery ever dies, it's simple to just pull start.

Used to have a pull start 40hp that wasn't bad to turn over.

The only issue with the battery is what parasitic draws do you have. If there is a bilge pump that runs periodically, that could kill the battery much quicker and the small trickle charger isn't likely to solve the issue.

The only issue with the battery is what parasitic draws do you have. If there is a bilge pump that runs periodically, that could kill the battery much quicker and the small trickle charger isn't likely to solve the issue.

Only 15-hp, with pull-start... and I've been using that; it's easy enough.